Two hummingbirds (Amazilia Beryllina) are trapped in a net set by biologists in a pollination garden set by the National Autonomous University of Mexico (UNAM) in Mexico City

Omar TORRES, AFP

She got her inspiration from former US first lady Michelle Obama, who included a variety of flowers in her famous White House garden to attract bees -- another threatened pollinator.

The university's hummingbird gardens feature specialized feeders as well as brightly colored, tubular flowers that attract the birds, which are known for hovering in the air as they drink their nectar, flapping their wings up to 200 times per second.

The gardens also have nets so scientists can capture the birds, tag and release them, enabling researchers in Mexico, the United States and Canada to track their migration patterns and monitor the impact of climate change.

A biologist feeds a hummingbird in Mexico City, where a project launched in 2014 is helping the birds along their long migratory route

Omar TORRES, AFP

Delicately holding the minute birds in their hands, Arizmendi and her fellow researchers fit them with tiny aluminum anklets, inscribed with ID numbers so small they can only be read with a magnifying glass.

Launched in 2014, the project now has five gardens around the Mexico City metropolitan area, and has inspired private citizens to create dozens of others -- all of which help feed hummingbirds on their long migratory route, which stretches from Alaska to South America.

"You don't have to live in the White House. It doesn't matter if you have a big yard or just a flower pot. If people attract and feed these birds, using whatever space they have, it contributes enormously to conserving the species," says Arizmendi.

A biologist checks the physical condition of a hummingbird, a species whose threats include climate change

Omar TORRES, AFP

Mexico City has 17 of the world's 330 hummingbird species. Of those, one is threatened, one is endangered and one is critically endangered: the short-crested coquette (Lophornis brachylophus).